1. Field
This disclosure relates to a magnesium compound, an electrolyte solution for magnesium batteries that includes the magnesium compound, and a magnesium battery including the electrolyte solution, and more particularly, to a magnesium compound that allows reversible dissolution and precipitation of magnesium and may improve the oxidation potential of an electrolyte solution, and an electrolyte solution including the magnesium compound, and a magnesium battery including the electrolyte solution.
2. Description of the Related Art
Recently, there has been an increasing interest in materials for power storage batteries.
Magnesium batteries are environmentally friendly, have competitive pricing, and offer high energy storage characteristics, as compared with existing lithium batteries, lead storage batteries, nickel-cadmium (Ni—Cd) batteries, nickel-hydrogen batteries, and nickel-zinc batteries. Accordingly, magnesium batteries are increasingly being researched.
In general, a magnesium battery includes a cathode containing a metal sulfide active material, such as Mo6S8, in bulk form, an anode containing a magnesium active material, such as magnesium or an alloy thereof, and an electrolyte solution including a magnesium salt dissolved in an organic solvent.
A common electrolyte solution for magnesium batteries is prepared by dissolving a Grignard magnesium salt and a Lewis acid containing a halogen in an ether solvent. The electrolyte solution contains chemical species formed between magnesium halide cations and organic anions. Such a ligand compound of magnesium halide cations and organic anions has a very low oxidation potential.
Accordingly, electrochemical stability of the electrolyte solution may depend upon oxidation resistance of the magnesium halide cations and the organic anions. In general, a ligand compound of a magnesium halide cations and organic anions has a low oxidation/reduction potential. For this reason, a cathode active material having a low oxidation/reduction potential is used.
When using a cathode active material having a high oxidation/reduction potential to increase energy density of a magnesium battery, decomposition may occur on a surface of the cathode active material due to a side reaction caused by oxidation of the electrolyte solution, which may limit a driving voltage of the magnesium battery.
Therefore, there remains a demand for a magnesium battery including an electrolyte solution that is stable at high voltages.